npm/workspaces/arborist/lib/peer-entry-sets.js

78 lines
2.6 KiB
JavaScript

// Given a node in a tree, return all of the peer dependency sets that
// it is a part of, with the entry (top or non-peer) edges into the sets
// identified.
//
// With this information, we can determine whether it is appropriate to
// replace the entire peer set with another (and remove the old one),
// push the set deeper into the tree, and so on.
//
// Returns a Map of { edge => Set(peerNodes) },
const peerEntrySets = node => {
// this is the union of all peer groups that the node is a part of
// later, we identify all of the entry edges, and create a set of
// 1 or more overlapping sets that this node is a part of.
const unionSet = new Set([node])
for (const node of unionSet) {
for (const edge of node.edgesOut.values()) {
if (edge.valid && edge.peer && edge.to) {
unionSet.add(edge.to)
}
}
for (const edge of node.edgesIn) {
if (edge.valid && edge.peer) {
unionSet.add(edge.from)
}
}
}
const entrySets = new Map()
for (const peer of unionSet) {
for (const edge of peer.edgesIn) {
// if not valid, it doesn't matter anyway. either it's been previously
// peerConflicted, or it's the thing we're interested in replacing.
if (!edge.valid) {
continue
}
// this is the entry point into the peer set
if (!edge.peer || edge.from.isTop) {
// get the subset of peer brought in by this peer entry edge
const sub = new Set([peer])
for (const peer of sub) {
for (const edge of peer.edgesOut.values()) {
if (edge.valid && edge.peer && edge.to) {
sub.add(edge.to)
}
}
}
// if this subset does not include the node we are focused on,
// then it is not relevant for our purposes. Example:
//
// a -> (b, c, d)
// b -> PEER(d) b -> d -> e -> f <-> g
// c -> PEER(f, h) c -> (f <-> g, h -> g)
// d -> PEER(e) d -> e -> f <-> g
// e -> PEER(f)
// f -> PEER(g)
// g -> PEER(f)
// h -> PEER(g)
//
// The unionSet(e) will include c, but we don't actually care about
// it. We only expanded to the edge of the peer nodes in order to
// find the entry edges that caused the inclusion of peer sets
// including (e), so we want:
// Map{
// Edge(a->b) => Set(b, d, e, f, g)
// Edge(a->d) => Set(d, e, f, g)
// }
if (sub.has(node)) {
entrySets.set(edge, sub)
}
}
}
}
return entrySets
}
module.exports = peerEntrySets